1. Technical Field
The present invention relates to a gas laser oscillator that oscillates laser using laser gas as a medium.
2. Description of the Related Art
When performing laser oscillation in a gas laser oscillator installed in a laser processing machine, the pressure of laser gas is controlled to a predetermined magnitude. If a gas pressure in a gas container fluctuates, the magnitudes of voltage and current to excite the laser gas fluctuate as well, a result of which laser output changes. Accordingly, in order to achieve stable laser output, high speed and high precision control of laser gas pressure is needed.
The gas pressure in the gas container is controlled by adjusting an amount of laser gas supplied into the gas container and an amount of laser gas exhausted from the gas container. For example, JP 2013-042000 A and JP H05-226731 A disclose a gas laser oscillator configured such that a control valve is provided at one of a laser gas supply unit and a laser gas exhaustion unit to supply or exhaust a constant amount of laser gas.
However, in order to improve the accuracy of gas pressure control, it is necessary to repeatedly carry out supply and exhaustion of laser gas in a short period of time, which results in an increase in the amount of consumption of the laser gas, thereby increasing the operation cost of the gas laser oscillator. JP 2013-026302 A, JP H01-179479 A, JP H03-166784 A, and JP H04-176178 A disclose a technique for controlling a consumption amount of laser gas using detection means for detecting a supply amount of the laser gas and an exhaust amount of the laser gas. However, such gas laser oscillators need to be provided with an additional detection means, thus increasing the cost.
Accordingly, there is a need for an inexpensive gas laser oscillator that can execute gas pressure control at high speed and with high precision and also can control the consumption amount of laser gas.